Supersonic gas flow impacting approach for solid-state synthesis at room-temperature: Temperature measurement

Solid-state synthesis based on supersonic gas flow impingement at room-temperature is an alternative approach to traditional mechanochemical preparation. The supersonic airflow is generated by a convergent-diffusion nozzle with a design Mach number of 3.0. The solid material particles from the suction pipe in the coaxial nozzle can get very high kinetic energy in microseconds. Then the particles impact the target or collide with each other to achieve the transfer of kinetic energy to thermal or chemical energy. We utilize the infrared technology to successfully measure the solid particles’ temperature while they impact the target after gathered energy from the supersonic air gas. The results show that the average temperature of the silicon particles with an average particle diameter of 150 $\mu$m after impacting the target is about $60^{\circ }$C, and some of the temperature exceed $200^{\circ }$C. It dedicates that the kinetic energy of the particles during the collision translate into internal energy indeed. The work of this paper lays a good foundation for further research on the low-temperature solid-phase reaction processes.